Glycopeptide antibiotic L 17046

ABSTRACT

The present invention is directed to a new antibiotic substance arbitrarily denominated antibiotic L 17046. This antibiotic substance is obtained from the known antibiotic substance called teicoplanin (formerly teichomycin) by chemical treatment. The new compound possesses antimicrobial activity especially against gram-positive bacteria.

The present invention is directed to a new antibiotic substancearbitrarily denominated antibiotic L 17046. This antibiotic substance isobtained from teicoplanin by chemical treatment.

Teicoplanin is the international non-proprietary name (INN) of theantibiotic substance formerly named teichomycin which is obtained bycultivating the strain Actinoplanes teichomyceticus nov. sp. ATCC 31121in a culture medium containing assimilable sources of carbon, nitrogenand inorganic salts (see U.S. Pat. No. 4,239,.751). According to theprocedure described in the above cited patent an antibiotic mixturecontaining teicoplanin A₁, A₂ and A₃ is recovered from the separatedfermentation broth by extraction with a suitable water insoluble organicsolvent and precipitation from the extracting solvent according tocommon procedures. Teicoplanin A₂, which is the the major factor of theisolated antibiotic complex, is then separated from the obtainedantibiotic mixture by means of column chromatography on Sephadex®.

British Patent Application Publication No. 2121401 discloses thatantibiotic teicoplanin A₂ actually is a mixture of five closely relatedco-produced factors.

Surprisingly, it has now been found that it is possible to transformteicoplanin A₂, each of its single factors or a mixture thereof, into adifferent derivative which possesses antimicrobial activity. This newantibiotic substance is denominated antibiotic L 17046. Thetransformation is essentially a chemical transformation. In fact, undercontrolled acid hydrolysis conditions, teicoplanin, or the individualconstituent factors thereof, gives antibiotic L 17046.

More particularly, the acid hydrolysis of teicoplanin, its singlefactors or a mixture thereof, in rather strong acidic conditions givesantibiotic L 17046. The concentration of the hydrolyzing agent was foundto be critical. Good results can be obtained by using 1 N hydrochloricacid. However, in general, higher concentrations (up to about 3 N) canbe conveniently used, depending on the reaction temperature and time. Asit is apparent to the man skilled in the art, similar results can beobtained by using substantially equivalent acidic conditions, such asanother mineral or organic acid of similar strength at similarconcentration. The temperature can be varied depending on the strengthof the mineral acid used and the reaction time. Good result are obtainedby carrying out the reaction at a temperature between 70°-90° C.,especially when using hydrochloric acid at a concentration between 1 Nand 3 N. The reaction time, in turn, varies very much depending on thespecific reaction conditions, i.e. type and concentration of the acidand reaction temperature. In general, the reaction is complete in about40-60 minutes or more.

A co-pending application describes selective hydrolysis of teicoplaninA₂ or a pure factor thereof for producing an antibiotic substancedenominated antibiotic L 17054. The hydrolysis is carried out underacidic conditions. The most preferred hydrolysis conditions are taughtto be: the presence of about 0.5 N hydrochloric acid and a temperatureof about 70°-90° C. for about 45-90 min.

This antibiotic substance (antibiotic L 17054) can in turn betransformed into the compound of the present invention by reacting itessentially under the same hydrolysis conditions as described above forthe production of antibiotic L 17046 from teicoplanin A₂ or the purefactors threof. However, a slightly lower temperature (for example,between 50° and 70° C.), and a shorter reaction time (for example, 20 to40 minutes) can be conveniently employed for this transformation.Although, in general, the process of the invention is preferablyconducted by using a single mineral acid, it may be possible to use amixture of different acids in order to obtain reaction conditionssimilar to those outlined above when dealing with a single hydrolyzingagent. In general, the possibility of these substitutions and thesuitable mixtures of hydrolytic agents are apparent to the skilled manwho is also able to select the proper reaction temperature and time onthe basis of what is disclosed in the present application and what isgenerally known in the art. Each reaction step is monitored, as known inthe art, by means of TLC or preferably HPLC technics. Alsochromatographic techniques coupled with bioassay tests (e.g.autobioassay) using microorganisms susceptible to the antibioticsubstance L 17046 can be conveniently used.

The compound which forms, antibiotic L 17046, is in general insoluble inhighly concentrated mineral acids and precipitates. Precipitation may beaided as known in the art, for instance, by addition of non-solvents.The recovered crude product is then purified preferably by means ofchromatographic techniques. In particular, partition columnchromatography is preferred. A preferred absorbent is in this caseuniform particle-size silica gel.

The eluent is preferably a mixture of acetonitrile and water, but eluentmixtures of solvents having a similar polarity can be conveniently used.

The preferred eluent mixture is represented by a linear gradient mixtureof acetonitrile and water from about 83:17 to about 70:30. The flow rateis preferably about 357 ml/h.

The elution is monitored by chromatographic assays, preferably HPLC.

The collected fractions are pooled according to the antibiotic content.Pure antibiotic L 17046 is then recovered by following known per setechniques, such as precipitation by non-solvents, filtration orextraction with solvents, concentration to a small volume andprecipitation.

Antibiotic L 17046 has the following characteristics:

(a) the specific rotation [α]_(D) ²⁰ is -44° (c=1%, DMF)

(b) it is freely soluble in water at pH>8.0, in dimethylformamide,dimethylsulfoxide, propyleneglycol and methylcellosolve; sligltlysoluble in methanol; almost insoluble in n-hexane, ethyl ether andacetone.

(c) it has an ultraviolet absorption spectrum, which is given in FIG. 1of the accompnaying drawings, that exhibits the following absorptionmaxima:

in 0.1 N hydrochloric acid: λ_(max) 278 nm (E₁ cm^(1%) =67.1)

in 0.1 N sodium hydroxide: λ_(max) 297 nm (E₁ cm^(1%) =124.1)

in phosphate buffer pH 7.4: λ_(max) 277 nm (E₁ cm^(1%) =75.0)

(d) an infrared absorption spectrum in nujol, shown in FIG. 2 of theaccompanying drawings, with the following observable absorption maxima(cm⁻¹): 3700-2000, 2970-2850 (nujol), 1655, 1610, 1595, 1515, 1490, 1460(nujol), 1375 (nujol), 1300, 1230, 1145, 1060, 1010, 890, 850, 820, 720(nujol)

(e) an elemental analysis, after the sample has been previously dried atabout 140° C. under inert atmosphere (weight loss=8.4%), which indicatesthe following approximate percentage composition (average): carbon56.74%; hydrogen, 4.27%; nitrogen, 7.99%; chlorine, 5.11%; ashes, 0.6%

(f) the following R_(f) values in the TLC systems indicated below:

    ______________________________________                                               Elution system (v/v)  R.sub.f value                                    (I)    Acetonitrile/water 75:25                                                                            0.53                                                    (silica gel Merck 60 F.sub.254)                                        (II)   Acetonitrile/5% aqueous sodium sul-                                                                 0.54                                                    fate 30:70                                                                    (silica gel Merck silanized 60 F.sub.254)                              Visualization: UV-light at 254 nm; 3% ethanolic                               ninhydrine; 1% methanolic fluorescamine;                                      ______________________________________                                    

(g) a retention time (t_(R)) of 10.8 minutes when analyzed by reversedphase HPLC using a 150×4.0 mm Zorbax® ODS (5-6 μm) column (Zorbax is atrademark of the Dupont Co. for a octadecylsilane silica matrix), andeluting with a linear gradient from 0% to 50% solution B in solution Ain 40 minutes

solution A: 25 mM NaH₂ PO₄ /acetonitrile (9/1) buffered at pH 6.0 with0.1 N NaOH

solution B: 25 mM NaH₂ PO₄ /acetonitrile (3/7) buffered at pH 6.0 with0.1 N NaOH), with a flow rate of 2 ml/min.; (internal standard:3,5-dihydroxytoluene t_(R) 5.60 minutes)

(h) the ¹ H NMR spectrum registered at 270 MHz in DMSO-d₆ at 60° C. andwith a sample concentration of 20 mg/ml is reported in FIG. 3 (internalstandard, TMS δ=0.00 ppm).

Some of the ¹ H NMR data obtained after D₂ O exchange and selectivedecoupling experiments are as follows (δ ppm, multiplicity): 1.86, s;2.81, d; 3.5, dd; ˜3-4; 4.12, d; 4.32, d; 4.37, d; 4.56, s; 4.95, ddd;5.07, s; 5.31, d; 5.39, s; 5.51, s; 5.66, d; 6.12, d; 6.29, s; 6.32, s;6.37, s; 6.42, s; 6.60, d; 6.62, s; 6.64, d; 6.92, d; 7.09, s; 7.12, d;7.21, d; 7.25, d; 7.43, d; 7.64, d; 7.66, d; 7.70, d; 7.85, s; 8.12, d;8.46, d; ˜9.5, s.

(i) a potentiometric titration profile which shows three titrationslopes with pH1/2 values equal to 5.0 (one equivalent), 7.0 (oneequivalent), and 11 (five equivalents) in methylcellosolve:water 4:1upon titration with 0.01 N NaOH of the solution of the test compoundcontaining an excess of 0.01 N HCl in same solvent mixture

(1) an acidic function capable of forming salts

(m) a basic function capable of forming salt

(n) a sugar residue which is N-acetyl-D-glucosamine.

On the basis of the physico-chemical data and by comparison with otherglycopeptidic antibiotic substances, such as vancomycin and ristocetin,the following structure can tentatively be attributed to antibiotic L17046: ##STR1##

Physico-Chemical Characteristics of Antibiotic L 17054

Antibiotic L 17054 has the following characteristics:

(a) the specific rotation [α]_(D) ²⁰ is -34° (c=1%, DMF)

(b) it is freely soluble in water at pH>8.0, in dimethylformamide,dimethylsulfoxide, propyleneglycol and methylcellosolve; slightlysoluble in methanol; almost insoluble in ethyl ether and acetone.

(c) an ultraviolet absorption spectrum which has the followingabsorption maxima:

in 0.1 N hydrochloric acid: λ_(max) 278 nm (E₁ cm^(1%) =60.6)

in 0.1 N sodium hydroxide: λ_(max) 297 nm (E₁ cm^(1%) =118.8)

in phosphate buffer pH 7.4: λ_(max) 277 nm (E₁ cm^(1%) =70.3)

(d) an infrared absorption spectrum in nujol with the followingabsorption maxima (cm⁻¹): 3700-2000, 2970-2850 (nujol), 1655, 1610,1595, 1515, 1490, 1460 (nujol), 1375 (nujol), 1300, 1230, 1145, 1060,1020, 970, 890, 850, 820, 720 (nujol)

(e) an elemental analysis, after the sample has been previously dried atabout 140° C. under inert atmosphere (weight loss=7.8%), which indicatedthe following approximate percentage composition (average): carbon55.46%; hydrogen, 4.50%; nitrogen 7.20%; chlorine 4.67%; ashes 0.2%

(f) it has the following R_(f) values in the TLC systems indicatedbelow:

    ______________________________________                                               Elution system (v/v)  R.sub.f value                                    (I)    Acetonitrile/water 75:25                                                                            0.32                                                    (silica gel Merck 60 F.sub.254)                                        (II)   Acetonitrile/5% aqueous sodium sul-                                                                 0.61                                                    fate 30:70                                                                    (silica gel Merck silanized 60 F.sub.254)                              Visualization: UV-light at 254 nm; 3% ethanolic ninhydri-                     ne; 1% methanolic fluorescamine;                                              ______________________________________                                    

(g) a retention time (t_(R)) of 8.3 minutes when analyzed by HPLC usinga 150×4.0 mm Zorbax® ODS (5-6 μm) column (Zorbax is a trademark of theDupont Co. for an octadecylsilane silica gel matrix), and eluting with alinear gradient from 0% to 50% solution B in solution A in 40 minutes(solution A: 25 mM NaH₂ PO₄ /acetonitrile (9/1) buffered at pH 6.0 with0.1 N NaOH; solution B: 25 mM NaH₂ PO₄ /acetonitrile (3/7) buffered atpH 6.0 with 0.1 N NaOH), with a flow rate of 2 ml/min.; (internalstandard: 3,5-dihydroxytoluene t_(R) 5.60 minutes)

(h) the ¹ H NMR spectrum is registered at 270 MHz in DMSO-d₆ at 60° C.and with a sample concentration of 20 mg/ml (internal standard, TMSδ=0.00 ppm). Some of the ¹ H NMR data obtained after D₂ O exchange andselective decoupling experiments are as follows (δ ppm, multiplicity):1.88, s; 2.85, d; ˜3.5, dd; 3-4; 4.20, d; 4.48, d; 4.50, d; 4.62, s;4.96, ddd; 5.18 d; 5.31, s; 5.35, d; 5.39, s; 5.68, d; 5.71, s; 6.20, d;6.41, s; 6.51, s; 6.56, s; 6.74, d; 6.77, s; 6.80, s; 6.80, d; 6.98, d;7.08, s; 7.15, d; 7.21, d; 7.28, d; 7.35, d; 7.50, d; 7.56, d; 7.64, d;7.73, d; 7.86, s; 8.42, d.

(i) a potentiometric titration profile which shows three titrationslopes with pH1/2 values equal to 5.0 (one equivalent), 7.0 (oneequivalent), and 11 (five equivalents) in methylcellosolve:water 4:1upon titration with 0.01 N NaOH of the solution of the test compoundcontaining an excess of 0.01 N HCl in the same solvent mixture

(1) an acidic function capable of forming salts

(m) a basic function capable of forming salts

(n) two sugar residues which are D-mannose and N-acetyl-D-glucosamine.

Antibiotic L 17046 possesses acid and basic functions capable of formingsalts respectively with bases and acids and therefore it can betransformed into its pharmaceutically acceptable acid and/or basicaddition salts according to procedures known per se in the art. The acidaddition salts are prepared as known in the art, preferably by usingmineral acids or rather strong acids in general such as hydrohalic,sulfuric, phosphoric, nitric, acetic, citric, aspartic, methanesulfonic,toluenesulfonic, or sulfanilic acid.

The basic addition salts, such as the alkali metal, the alkaline earthmetal, the ammonium and organic ammonium salts such as the alkylammoniumsalts are prepared as known in the art. In some instances they can bepreferred in view of their easy preparation and desirable solubilityproperties. The basic addition salts also encompass basic aminoacidaddition salts such as the lysine, arginine or glycine salts.

In view of the similarity of the properties of antibiotic L 17046 andits salts, what is said in the present application when dealing with thebiological activities of antibiotic L 17046 applies also to itspharmaceutically acceptable salts.

The in vitro antibacterial activity of antibiotic L 17046, which showedto be mainly active against gram-positive bacteria, was determined byusing the two-fold dilution method in microtiter system. Isosensitestbroth (Oxoid) and Todd-Hewitt broth (Difco) were used for Staphylococciand Streptococci, respectively. Broth cultures were diluted so that thefinal inoculum was about 10⁴ colony forming units/ml (CFU/ml). Minimalinhibitory concentration (MIC) was considered as the lowestconcentration which showed no visible growth after 18-24 h incubation at37° C. The obtained results are summarized in TABLE I below:

                  TABLE I                                                         ______________________________________                                        In vitro antibacterial activity of antibiotic L 17046                         Microorganism           MIC (μg/ml)                                        ______________________________________                                        Staphylococcus aureus ATCC 6538                                                                       0.2                                                   Staplylococcus aureus Tour                                                                            0.2                                                   Staplylococcus aureus Tour                                                                            0.4                                                   (Isosensitest broth + 30% bovine serum)                                       Staphylococcus epidermidis ATCC 12228                                                                 0.05                                                  Streptococcus pyogenes C 203                                                                          1.6                                                   Streptococcus dysgalactiae ATCC 9926                                                                  0.8                                                   Streptococcus faecalis ATCC 7080                                                                      1.6                                                   Streptococcus pneumoniae UC 41                                                                        1.6                                                   ______________________________________                                    

Antibiotic L 17046 was found to be particularly effective againstcoagulase-negative staphylocci (S. epidermidis, S. saprophyticus).

Its MICs (g/ml) against some clinical isolates of the above microbialstrains are listed below in Table II:

                  TABLE II                                                        ______________________________________                                        Strains          MIC (μg/ml)                                               ______________________________________                                        S. epidermidis *L 785                                                                          0.05                                                         S. epidermidis L 1378                                                                          0.05                                                         S. epidermidis *L 835                                                                          0.1                                                          S. epidermidis *L 1142                                                                         0.1                                                          S. saprophyticus L 1141                                                                        0.1                                                          ______________________________________                                         *Methicillin-resistant strains                                           

The antimicrobial activity of the compound of the invention is confirmedalso in in vivo experiments.

The approximate acute toxicity in mice (i.p.) of antibiotic L 17046 wasevaluated according to methods known in the art and the approximate LD₅₀was found to be about 850 mg/kg in mice administered by i.m. route.

In view of the above, the compound of the present invention caneffectively be employed as the active ingredient of antimicrobialpreparations used in human and veterinary medicine for the preventionand treatment of infectious diseases caused by pathogenic bacteria whichare susceptible to said active ingredients. The compounds of the presentinvention can be administered orally, topically or parenterally.However, the parenteral and topical routes of administration arepreferred. Particularly preferred are those pharmaceutical formulationssuitable for intramuscular administration. Depending on the route ofadmnistration, these compounds can be formulated into various dosageforms. The formulation of suitable pharmaceutical compositions can becarried out by the skilled man according to the general common knowledgein the art with the auxilium of reference books, such as the"Remington's Pharmaceutical Sciences" Handbook, Mack Publishing Company,U.S.A., 15th Edition, 1975.

For topical use the compounds of the present invention may be preparedin suitable forms for absorption through the mucous membranes of thenose and throat or bronchial tissues and may conveniently take the formof liquid sprays or inhalants, lozenges, or throat paints. Formedication of the eyes or ears, the preparation may be presented inliquid or semi-liquid form. Topical applications may be formulated inhydrophobic or hydrophilic bases as ointments, creams, lotions, paints,or powders.

Compositions for injection may take such forms as suspensions,solutions, or emulsions in oily or aqueous vehicles, and may containformulatory agents such as preservative, suspending, stabilizing and/ordispersing agents.

Alternatively, the active ingredient may be in powder form forreconstitution, at the time of delivery, with a suitable vehicle, suchas sterile water.

The active compound may also be formulated into suppositories forrectal, vaginal or urethral administration. The excipient are thoseusually used in these preparations such as polyvinylpyrrolidone, cocoabutter, triglycerides of C₁₂ -C₁₈ fatty acids, polyethylene glycols andsurface-active agents.

The amount of compound administered will vary with the severity of theinfection, the nature and body weight of the patient, the type andformulation in which the active ingredient is to be administered, themode of administration, the general health status of the patient, andthe interval between each subsequent administration.

In consideration of the above parameters, sometimes it may be necessaryto deviate from the dosage-range indicated. In general, antibiotic L17046 and its pharmaceutically acceptable salts are effective at a dailydosage comprised between about 0.1 and about 20 mg of active ingredientper Kg of body weight, preferably divided in 2 to 4 administrations perday.

Particularly desirable compositions are those prepared in the form ofdosage units containing from about 5 to about 250 mg of the activeprinciple per unit.

Representative examples of preparation of pharmaceutical compositionsare as follows:

A parenteral solution is prepared with 100 mg of antibiotic L 17046sodium salt dissolved in 2 ml of sterile water for injection

A parenteral solution is prepared with 250 mg of antibiotic L 17046sodium salt dissolved in 3 ml of sterile water for injection

A topical ointment is prepared with 200 mg of antibiotic L 17046; 600 mgof polyethylene glycol 4000 U.S.P; 1.2 g of polyethylene glycol 400U.S.P.

Besides their activity as medicaments, the compound of the presentinvention can be used as animal growth promoters.

For this purpose, the compound of the invention are administered orallyin a suitable feed. The exact concentration employed is that which isrequired to provide for the active agent in a growth promotant effectiveamount when normal amounts of feed are consumed.

The addition of the active compounds of the invention to animal feed ispreferably accomplished by preparing an appropriate feed premixcontaining the active compounds in an effective amount and incorporatingthe premix into the complete ration.

Alternatively, an intermediate concentrate or feed supplement containingthe active ingredient can be blended into the feed.

The way in which such feed premixes and complete rations can be preparedand administered are described in reference books (such as "AppliedAnimal Nutrition", W. H. Freedman and Co., S. Francisco, USA, 1969 or"Livestock Feeds and Feeding", O and B Books, Corvallis, Oreg., USA,1977) and are incorporated herein by reference.

The following examples illustrate the manner in which the invention canbe practiced, but, as such, should not be construed as limiting itsoverall scope.

Example 1: Preparation of antibiotic L 17046 from teicoplanin

Teicoplanin A₂ (10 g) is added to 1 N hydrochloric acid (150 ml)preheated to 80° C. while stirring. After about 45 minutes the reactionmixture is cooled to 0°-5° C. and 37% hydrochloric acid (30 ml) isadded. Stirring is maintained for about 10 minutes, after which theprecipitated solid is recovered by filtration, washed with 20 ml of 2 NHCl, then with ethyl ether, and dried overnight over potassium hydroxidepellets at room temperature, resulting in the crude product of the title(8.3 g).

Example 2: Purification of crude antibiotic L 17046

The above crude product (6.2 g) is dissolved in 80% methanol (500 ml)and silica gel (30 g; Merck 0.06-0.2 mm) is added. After the addition ofn.butanol (200 ml) the solvent is removed under vacuum. The residue isthen applied to a silica gel chromatography column (300 g) inacetonitrile.

The column is developed by using sequentially 300 ml each of thefollowing solvent mixtures:

acetonitrile, acetonitrile:water 95:5, acetonitrile:water, 90:10;acetonitrile:water, 85:15.

The eluates are discarded and the column is developed with a lineargradient eluent obtained by mixing 3.51 each of the following mixtures:

acetonitrile:water, 83:17 and acetonitrile:water, 70:30 at a rate of 375ml/h.

Fractions of 25 ml each are collected and monitored by HPLC. Thefractions which contain antibiotic L 17046 (fractions 170 to 200) arecombined. n-Butanol (400 ml) is added to the pooled fractions and theresulting mixture is concentrated to a small volume. Acetone is thenadded to the cloudy solution and, after cooling to 10° C. a precipitatebegins to form. After suitable time, the precipitation is complete andthe solid is then collected by filtration, washed with acetone, thenwith ether, dried under vacuum at room temperature, yielding the purecompound of the title (1.9 g).

Example 3: Preparation of antibiotic L 17046 from antibiotic L 17054

(a) Preparation of antibiotic L 17054

5 g of teicoplanin are added to 60 ml of 0.5 N aqueous hydrochloric acidpre-heated to 80° C. with vigorous stirring.

Stirring is continued and the temperature is maintained at about 80° C.for 30 minutes. Then, the mixture is rapidly filtered, the filtrate iscooled to 0°-5° C. and 6 N hydrochloric acid (10 ml) is added. Theresulting suspension is stirred for about 15 minutes while keeping thetemperature at 0°-5° C. The precipitate is collected, washed and driedunder reduced pressure at room temperature resulting in crude antibioticL 17054 (4.5 g).

Crude antibiotic L 17054 (3 g) as obtained in Example 1 is suspended ina mixture of 0.2% aqueous HCOONH₄ :CH₃ CN 95:5 (v/v) (150 ml).

The pH is brought to pH 7.5 with 1 N NaOH and the product is dissolved.The resulting solution is applied to a column containing 150 g of0.06-0.2 mm silanized silica gel (Merck) prepared in the same solventmixture. The column is developed with a linear gradient elution, from 5to 21% of acetonitrile in 0.2% aqueous ammonium formate (v/v),collecting 20 ml fractions, which are monitored by HPLC. L 17054containing fractions (70 to 96) are combined and the acetonitrile isremoved under vacuum. The residual aqueous solution is applied to acolumn of 10 g of silanized silica gel in distilled water. After washingwith distilled water until the salts are completely eliminated theproduct is eluted with a 1:1 (v/v) CH₃ CN:H₂ O mixture.

The collected solution is concentrated under vacuum to a small volume,acidified to pH 3.5 with 1 N HCl and the antibiotic is precipitated byadding acetone. After drying at room temperature, 0.9 g of pureantibiotic L 17054 is obtained.

(b) Production of antibiotic L 17046:

1 N Hydrochloric acid (15 ml) is heated to 80° C. and the antibiotic L17054 (1 g) is added, while keeping the temperature at 80° C. Thestirred mixture is kept at this temperature for about 30 minutes, thenit is cooled to 0°-5° C. and 37% hydrochloric acid (1 ml) is added.Stirring is maintained for about 10 minutes, then the solid is recoveredby filtering, washing and drying under reduced pressure, at roomtemperature, overnight resulting in the crude antibiotic L 17046 (0.5 g)which can be purified essentially as described above in Example 2.

We claim:
 1. A compound selected from antibiotic L 17046 and itspharmaceutically acceptable salts which has the followingcharacteristics, in the non-salt form:(a) the specific rotation [α]_(D)²⁰ is -44° (c=1%, DMF) (b) it is freely soluble in water at pH>8.0, indimethylformamide, dimethylsulfoxide, propyleneglycol andmethylcellosolve; slightly soluble in methanol; almost insoluble inn-hexane, ethyl ether and acetone, (c) it has an ultraviolet absorptionspectrum that exhibits the following absorption maxima:in 0.1 Nhydrochloric acid: λ_(max) 278 nm (E₁ cm^(1%) =67.1) in 0.1 N sodiumhydroxide: λ_(max) 297 nm (E₁ cm^(1%) =124.1) in phosphate buffer pH7.4: λ_(max) 277 nm (E₁ cm^(1%) =75.0) (d) an infrared absorptionspectrum in nujol with the following observable absorption maxima(cm⁻¹): 3700-2000, 2970-2850 (nujol), 1655, 1610, 1595, 1515, 1490, 1460(nujol), 1375 (nujol), 1300, 1230, 1145, 1060, 1010, 890, 850, 820, 720(nujol) (e) an elemental analysis, after the sample has been previouslydried at about 140° C. under inert atmosphere (weight loss=8.4%), whichindicates the following approximate percentage composition (average):carbon 56.74%; hydrogen, 4.27%; nitrogen, 7.99%; chlorine, 5.11%; ashes,0.6% (f) the following R_(f) values in the TLC systems indicated below:

    ______________________________________                                               Elution system (v/v)  R.sub.f value                                    (I)    Acetonitrile/water 75:25                                                                            0.53                                                    (silica gel Merck 60 F.sub.254)                                        (II)   Acetonitrile/5% aqueous sodium sul-                                                                 0.54                                                    fate 30:70                                                                    (silica gel Merck silanized 60 F.sub.254)                              Visualization: UV light at 254 nm; 3% ethanolic                               ninhydrine; 1% methanolic fluorescamine;                                      ______________________________________                                    

(g) a retention time (t_(R)) of 10.8 minutes when analyzed by reversedphase HPLC using a 150×4.0 mm Zorbax® ODS (5-6 μm) column (Zorbax is atrademark of the Dupont Co. for a octadecylsilane silica matrix) andeluting with a linear gradient from 0% to 50% solution B in solution Ain 40 minutessolution A: 25 mM NaH₂ PO₄ /acetonitrile (9/1) buffered atpH 6.0 with 0.1 N NaOH solution B: 25 mM NaH₂ PO₄ /acetonitrile (3/7)buffered at pH 6.0 with 0.1 N NaOH), with a flow rate of 2 ml/min.;(internal standard: 3,5-dihydroxytoluene t_(R) 5.60 minutes) (h) the ¹ HNMR spectrum registered at 270 MHz in DMSO-d₆ at 60° C. and with asample concentration of 20 mg/ml is reported in FIG. 3 (internalstandard, TMS δ=0.00 ppm), some of the ¹ H NMR data obtained after D₂ Oexchange and selective decoupling experiments are as follows (δ ppm,multiplicity): 1.86, s; 2.81, d; 3.5, dd; ˜3-4; 4.12, d; 4.32, d; 4.37,d; 4.56, s; 4.95, ddd; 5.07, s; 5.31, d; 5.39, s; 5.51, s; 5.66, d;6.12, d; 6.29, s; 6.32, s; 6.37, s; 6.42, s; 6.60, d; 6.62, s; 6.64, d;6.92, d; 7.09, s; 7.12, d; 7.21, d; 7.25, d; 7.43, d; 7.64, d; 7.66, d;7.70, d; 7.85, s; 8.12, d; 8.46, d; ˜9.5, s, (i) a potentiometrictitration profile which shows three titration slopes with pH1/2 valuesequal to 5.0 (one equivalent), 7.0 (one equivalent), and 11 (fiveequivalents) in methylcellosolve:water 4:1 upon titration with 0.01 NNaOH of the solution of the test compound containing an excess of 0.01 NHCl in the same solvent mixture (1) an acidic function capable offorming salts, (m) a basic function capable of forming salts, (n) asugar residue which is N-acetyl-D-glucosamine.
 2. Antibiotic L 17046 ora pharmaceutically acceptable salt thereof, characterized by thefollowing formula, in the non-salt form: ##STR2##